258 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



sandy beds without a pebble in them. During Cretaceous times 

 and afterwards there is evidence of the connection, perhaps by an 

 isthmus, with the North-East Himalayan area, across the present 

 Gangetic Delta, the line of coast lying then on the north side of the 

 present more recent elevation of the Khasi Hill range. All this, 

 briefly stated, supports the possibility that the genera and species of 

 to-day are the direct descendants of the moUuscan fauna of a very 

 early time, and the survivors of many changes. How far they have 

 been modified, how old some may be, only the evidence of fossil forms 

 can show, I here revert to remarks made at the commencement of 

 this address, on the importance of trying strenuously to find some of 

 these fossil representatives, and, if possible, arrive at what has been the 

 extent of the changes and in what direction. Evidence exists, but as 

 yet it has been superficially worked. Take, for example, the Cretaceous 

 fossils, which are far too ancient for us to expect that any very close 

 resemblance with the present forms would be shown ; yet only four 

 species of Helix have been found in South India ; ^ probably this is not 

 a quarter of what may be preserved.'^ Coming to the inter-Trappean 

 beds and the Tertiaries, patient search will no doubt be rewarded- — it 

 cannot fail to be — with an addition to the number of fossil land-shells 

 of the very greatest interest and value. "What we want to know is at 

 what period and to what extent changes in the molluscan fauna of 

 India have taken place. Mr. W. T. Elanford has dealt with this 

 inquiry, and on the evidence of what has been hitherto found 

 writes : — ^ "All the forms known from the Upper Siwaliks, with one 

 exception, are recent species of land and fresh-water shells now living 

 in the area. Of seven fresh- water mollusca'' found associated with the 

 Lower Siwaliks, none appears to be identical with any living species, 

 and only two are allied, one closely, the other more remotely, to forms 

 now met with in Burmah, 30° of longitude further east. . . . One- 

 third of the species of mammalia survived the changes that took place, 

 whereas not a single moUusk is found both in the Upper and Lower 

 Siwaliks." 



In conclusion, let me say how exceedingly glad I am that my old 

 and very good friend for so many years follows me in this chair. The 

 Mollusca were an old love of his long ago, and he will, I hoj)e, at 

 some future meeting, favour us with his views on their distribution, 

 which his great knowledge in other orders will enable him to treat 

 of more fully than I have done. 



' These are three species of Anehistoma, having the character of Corilla or Flecto- 

 pylis, the first restricted to Ceylon and one species put in Macrocyclis. 



^ These land-shells are from deposits on the margin of the old Cretaceous coastline, 

 and others may be looked for in similarly situated deposits of that age. On the 

 Garo-Khasi boundary, for instance, \ 25'25, on the Trigonometrical Station of 

 Lumdekor, an outlier, a good section is to be seen. The pale-coloured, fine 

 silty deposits were full of the most beautifully preserved plant remains I have 

 ever seen, indicating the proximity of a forest-clad land. 



3 Eec. Geol. Surv. Ind., vol. xviii (1885), p. 38, pi. i. 



* Mem. Geol. Surv. Ind., vol. xx, pt. 2, p. 129. 



